Japan demo shows electricity entering EV through tires

Jul 08, 2012 by Nancy Owano weblog

(Phys.org) -- Electric vehicles' future continues to tease scientists to devise promising and practical ideas to keep these cars moving along the highways without having to pull over and wait for a battery recharge. Solutions for the so called “charging and range problem” took yet another twist this month when a Japanese university team demonstrated how electricity can be transmitted to a pair of tires through a four-inch-thick block of concrete, the type of concrete used on roads. The team took its demo to WTP (Wireless Technology Park) 2012, a trade show on wireless technologies, earlier this month in Yokohama.

Their solution is in the form of a wireless power prototype that can successfully transmit electricity through the concrete block. They consider the prototype as an early step to improve on, and that such an approach can be used one day to keep on the move.

Takashi Ohira, an electrical engineering professor at the Toyohashi University of Technology, who leads the team, has developed his electric field coupling system to supply a charge to a car through its . The goal is to enable power transmission as the vehicle’s tires travel along the road with suitable efficiency and power transfers.

In the demo, a metal plate was placed along with a four-inch layer of concrete, representing the road surface. Electricity between 50 and 60 watts was transmitted to actual-size automobile tires. The demo also showed a light bulb, attached between the two demo car tires, turning on.

The university team’s project is called EVER (Electric Vehicle on Electrified Roadway). The focus is research aimed at using wireless power transmission technologies based on electric field coupling for transmitting power to a running vehicle.

The July demo is the latest of similar past efforts by the researchers. Last year, Toyota Central R&D Labs and Ohira reported on their work to allow electric cars to drive unlimited distances on an electrified roadway. They reported a system that similarly transmits electric power through steel belts inside the two tires and a metal plate in the road. They presented their work at a workshop in Kyoto. To test how much energy would be lost as electricity traveled through the tire rubber, the researchers also set up a lab experiment with metal plates. "Less than 20 percent of the transmitted power is dissipated in the circuit," said Ohira at that time. With enough power the system could run typical passenger cars, he added.

To make their present technology useful, the electric needs to be increased by 100 times. But, moving ahead, the group said that they are up to the task of meeting the project's challenges.

Explore further: Going nuts? Turkey looks to pistachios to heat new eco-city

More information:
vit Techon

Related Stories

Japanese scientists explore electric roads for EVs

Sep 20, 2011

(PhysOrg.com) -- Masahiro Hanazawa of Toyota Central R&D Labs and Takashi Ohira from Toyohashi University are working on a solution for avoiding battery recharge headaches in powering electric cars. They are ...

Electric cars get charged wirelessly in London (w/ Video)

Nov 04, 2010

(PhysOrg.com) -- HaloIPT has recently demonstrated wireless charging of electric vehicles in London using their inductive power transfer technology. The company fitted Citroen electric cars with receiver pads ...

Cable-free charging of electric cars via coils

Apr 11, 2011

In the future, motorists will no longer need a cable to recharge the batteries of their electric cars, thanks to a development project for inductive charging, which Siemens presented at Hannover Messe 2011. ...

Qualcomm's HaloIPT tech brings wireless charging for EVs

Jan 16, 2012

(PhysOrg.com) -- Qualcomm has demonstrated its new wireless power transmission system for electric vehicles (EVs) at the Consumer Electronics Show (CES). The system, including one pad for power transmitting, ...

SIM-Drive Corp announces new 'in-wheel' electric car

Apr 01, 2011

(PhysOrg.com) -- SIM-Drive Corporation, a Japanese consortium based in Kawasaki-shi and comprised of 34 companies and municipalities, has announced that it has developed a functioning electric car based on ...

Recommended for you

Obama launches measures to support solar energy in US

Apr 17, 2014

The White House Thursday announced a series of measures aimed at increasing solar energy production in the United States, particularly by encouraging the installation of solar panels in public spaces.

Tailored approach key to cookstove uptake

Apr 17, 2014

Worldwide, programs aiming to give safe, efficient cooking stoves to people in developing countries haven't had complete success—and local research has looked into why.

User comments : 26

Adjust slider to filter visible comments by rank

Display comments: newest first

Eikka
3.1 / 5 (14) Jul 08, 2012
It has the same problem as power lines though. If you lay down a hundred miles of cable and send AC power through it, there is significant capacitive leakage to ground. Here even more so, because to maintain the coupling they need to use high frequency, which means high leakage currents as well.

20% is a massive loss when it comes to powering thousands of cars on the roads on its own, and it'll likely be much more when you consider that the system will run idle for a great deal of the time.

It's like the old engineering riddle question: in an apartment building lift/elevator, what part consumes the most energy? Most people would say it's the motor, but in reality it's the lightbulb in the box that is on 24/7.
ahaveland
not rated yet Jul 08, 2012
Remember Scalextric?
verkle
2.1 / 5 (11) Jul 08, 2012
Before we get into whether 20% loss is a massive number or not, we need to figure out how to transfer energy 100 times faster. Exciting field to be in. Leave it to the engineers!

jimbo92107
2 / 5 (4) Jul 08, 2012
If you combine power recycling with this technology, you could have pressure plates in the road returning power to cars as they pass over them. Then you're gaining back power normally wasted as heat. Combine that also with power recycled from the tires and shocks, and whatever losses you incur are far better than recovering nothing.
Newbeak
3.4 / 5 (5) Jul 08, 2012
The Achilles heel in these systems is the capital cost of burying thousands of miles of charging plates.The cost per mile would no doubt exceed that to build a railway line.Who picks up the tab?
jerryd
1 / 5 (5) Jul 08, 2012

This is so wrong on so many levels. It just isn't going to work 10% as well as a power arm style would with fewer parts, brushes. Also heating the already overheated tire with 20% of the power plus ramping up the power with the same resistance will increase losses to 80-90% or more.

Next if someone walks on the road ZAP!! I guess it's one way to control population growth ;^P

Just put a power slot down the road center done right like a slot car is far less costly, more eff.
Eikka
3.1 / 5 (9) Jul 08, 2012
Just put a power slot down the road center done right like a slot car is far less costly, more eff.


A slot car is effectively like a large spark gap emitter that ruins wireless for miles and miles as cars go by, and the tracks and brushes wear because of friction and electric pitting, requiring constant replacement and cleaning to keep the grime out.

Electric trains have the same problems with the pantographs, but there's a lot less wear on the cables because a single tractor can pull a hundred cars.

A wireless version would be the only sensible option if it was possible to make one without too much cost and loss of energy.
Isaacsname
4 / 5 (4) Jul 08, 2012
Going by previous comments, isn't this really just trying to make giant slot cars ?

Why not just use this for wireless docking in your driveway ?

Or embedded under parking spaces where you'd have an option to pay for a recharge while parked, etc, at work, whatever.
Eikka
1.9 / 5 (8) Jul 08, 2012
Why not just use this for wireless docking in your driveway ?


Because the dielectric losses would destroy the rubber wheels if they aren't spinning to spread the heat and cool them down.

If the charging station is stationary, you're better off using a cable.
Tewk
2 / 5 (4) Jul 08, 2012
If you combine power recycling with this technology, you could have pressure plates in the road returning power to cars as they pass over them. Then you're gaining back power normally wasted as heat. Combine that also with power recycled from the tires and shocks, and whatever losses you incur are far better than recovering nothing.


"Pressure plates" ? "power recycled from tires" ?

Please explain these things further.
Tewk
2.3 / 5 (6) Jul 08, 2012
Why not just use this for wireless docking in your driveway ?


Because the dielectric losses would destroy the rubber wheels if they aren't spinning to spread the heat and cool them down.


How do you know this ?
sennekuyl
1 / 5 (2) Jul 08, 2012
Magnetic interlocks seem to be the most viable method to me(magsafe for vehicles?). It could easily be combined with a smart docking system; in parking bays you can charge for recharging etc., while at home it could be automated. Eliminates the issues of high losses you would see with a wireless public road system.

Don't forget there would also be losses in the cars not charging as their secondary coils pass through the em field not to mention the losses in carrying around the secondary coils extra weight. Yes, they can be engineered out but ... 2 steps forward 1 back generally. Cabled solutions are here and more viable. Also most of the increase effectiveness for wireless solutions have a greater benefit using cables.

@Tewk: We know rubber breaks down under heat, & changing em fields generate heat, so it isn't hard to foresee that issue.

However, the tires get hot rolling due to friction anyway so I'm sure it has been solved already.
xen_uno
2 / 5 (4) Jul 08, 2012
Piezoelectric crystals embedded in the tires seems more realistic on a large scale than this. The best pavement concrete lasts a couple years at most in the northern latitudes before chipping, cratering, shifting, and deformation occurs. Repaving is expensive ... repaving with wires I would guess 2 to 4 times that.
sennekuyl
1 / 5 (1) Jul 08, 2012
Piezoelectric crystals don't generate nearly high enough power to charge vehicle batteries, so I don't thinks so.

At 4 inches (100mm for the modern minds) the wires would presumably below the majority of pot-holes, much deeper and the road has some serious engineering issues anyway. The cables would presumably be buried inside a suitable insulation other than concrete so that shouldn't be a large issue.

The biggest issues are stationary cable connections beat wireless in efficiency & effectiveness. Wireless is only slightly more convenient than cable is some situations. AFAICT, it adds complexity for only a small gain. Hopefully, the world adopts the more pragmatic solutions over convenience.

Not saying wireless solutions shouldn't be researched, just doubtful they should be implemented.
Estevan57
2.1 / 5 (29) Jul 09, 2012
Gino
not rated yet Jul 09, 2012
When I lived in Edmonton before the war the trams picked up their power from a underground slot but of course they had the rails upon which they where running for the return circuit.
antialias_physorg
4 / 5 (4) Jul 09, 2012
If you combine power recycling with this technology, you could have pressure plates in the road returning power to cars as they pass over them.

That won't work. You can't give car X the energy imparted by car Y because then car Y will effectively have a zero sum energy imparted to the road. Any energy that you additionally capture via compression/heat plates or whatnot has first to be produced somewhere as waste (i.e. your motor). There's no free lunch here.

The cost per mile would no doubt exceed that to build a railway line.

And advantage is that you could bury all your high voltage lines underground while you'r eat it (getting rid of al those transmission towers which are susceptible to all kinds of problems from high wind to lightning strikes)

Why not just use this for wireless docking in your driveway ?

Because this is for erange extension. The wireless dock in your driveway isn't.

antialias_physorg
3.7 / 5 (3) Jul 09, 2012
The real deal for this is in the combination of EVs that can go limited range on their own (anough for commutes, shopping trips, etc.) and getting the larger range when you need it (i.e. when you're going on highways and the charge you have in your batteries just needs to get you the first miles to and last miles off the highway)

It would also be perfect for creating 'road trains' on highways without the need of having a a lot of logic inside the cars. I think it would be a viable combination between personal transport system and still having an individual vehicle tailored to your needs (or hook in personal transport systems later as needed).
PS3
1 / 5 (4) Jul 09, 2012
Why not just generate it from the shocks.
LUV
3 / 5 (1) Jul 09, 2012
Some basic points. In 1996 the Solectria Sunrise got 375 miles per charge, Ford Echostar got 225 miles per charge, GM's EV-1 got 125 miles per charge. Nearly 20 years later they've actually regressed? How easy it would be to make an EV that is coated with thin-film PV so it is always charging anytime anywhere light is present, (Aleo solar thinfilm PV works equally well on cloudy days.) This EV would also have generators placed in certain wheels (even extra wheels) so electricity is also produced anytime the wheels move, regenerative braking would also feed electricity back into the onboard recharging system, the power saving system used in the Solectria would also be employed and power saving ultracapacitors (i.e., Maxwell technologies) would also be employed during acceleration greatly extending the battery charge life. You could also use the Nanosafe batteries. Doesn't this sound better and cheaper?
Deathclock
2.3 / 5 (3) Jul 09, 2012
"his EV would also have generators placed in certain wheels (even extra wheels) so electricity is also produced anytime the wheels move"

Is this troll physics? Why not just put a bunch of windmills on the car that generate electricity from the airflow at high speeds?
antialias_physorg
3 / 5 (2) Jul 09, 2012
How easy it would be to make an EV that is coated with thin-film PV so it is always charging anytime anywhere

Do the math. The charge you get from a full day sunlight wouldn't get you 5 miles extra range.

so electricity is also produced anytime the wheels move

When braking: yes...but generating energy from wheel motion? Either you just invented a perpetuum mobile or you haven't thought this one through at all.

(Braking energy and energy from shocks is also barely worth it. Given that you have to lug around additional tech - read: stuff that can break down and/or weighs a lot - to make it work.
Tewk
3 / 5 (4) Jul 10, 2012

Is this troll physics? Why not just put a bunch of windmills on the car that generate electricity from the airflow at high speeds?


As another poster stated above, there's no free energy. Any energy you'd get from those windmills would come from the engine of the car. Consider where does the energy come from that moves that car creating all that wind that drives the windmills . And then when to factor in all the losses involved due to friction etc., you end up at a loss.
Please don't hesitate to ask questions.

Eikka
3 / 5 (6) Jul 14, 2012
Some basic points. In 1996 the Solectria Sunrise got 375 miles per charge, Ford Echostar got 225 miles per charge, GM's EV-1 got 125 miles per charge. Nearly 20 years later they've actually regressed?


Apples to oranges. Solectria Sunrise and EV1 were two-seater sub-subcompact cars that would barely register as quadricycles today if it weren't for the massive weight of their batteries. The Solectria had 900 pounds of batteries onboard and yet had the same energy capacity as the Nissan Leaf has today.

The Ford Ecostar used an experimental sodium-sulfur battery and cost $250,000 a vehicle which is nearly $300,000 each in today's money, and actually averaged 94 miles per charge. I don't know where you picked up the 225 miles, unless it's again one of those "driving around a parking lot at 25 mph" tests.

Why didn't Ford continue with it?
However, on several occasions the battery burst into flame during recharging. For this, and several other reasons, Ford lost interest
Eikka
3 / 5 (6) Jul 14, 2012
Actually, the Ford Ecostar would have cost $397,603.81 in today's money.

If today Tesla can make an electric car at 1/8 of that price, that's really really impressive. With the same trend, we'll only have to wait about ten years more before the cheapest models become affordable and profitable to make.
barakn
2.3 / 5 (3) Jul 24, 2012
(Braking energy and energy from shocks is also barely worth it. Given that you have to lug around additional tech - read: stuff that can break down and/or weighs a lot - to make it work.

DC motors can also be generators, and wouldn't require much extra equipment. Thus regenerative braking is an active area of research.

More news stories

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

A homemade solar lamp for developing countries

(Phys.org) —The solar lamp developed by the start-up LEDsafari is a more effective, safer, and less expensive form of illumination than the traditional oil lamp currently used by more than one billion people ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...